scholarly journals Shallow Geophysical Techniques to Investigate the Groundwater Table at the Giza Pyramids Area, Giza, Egypt

2017 ◽  
Author(s):  
Sharafeldin M. Sharafeldin ◽  
Khalid S. Essa ◽  
Mohamed A. S. Youssef ◽  
Zein E. Diab
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Seismic Refraction ◽  
Groundwater Table ◽  
High Resistivity ◽  
Electrical Resistivity Imaging ◽  
Shallow Seismic ◽  
Geophysical Techniques ◽  
Electrical Resistivities ◽  
Ground Penetrating

Abstract. Geophysical studies were performed along selected locations across the Pyramids Plateau to investigate the groundwater table and the near aquifer, which harmfully affected the existed monuments of the Giza Pyramids and Sphinx. Electrical Resistivity Imaging (ERI), Shallow Seismic Refraction (SSR) and Ground Penetrating Radar (GPR) techniques were carried out along selected profiles in the plateau. Ten ERI, twenty six SSR and nineteen GPR profiles were performed at the sites. The ERI survey shows that, the groundwater table is at elevations varying from 13 to 18 m above the sea level (asl) and low resistivity values near the surface at the Great Sphinx. ERI profiles, which were applied southeast of the Middle Pyramid (Khafre), show high resistivity values near the surface, and water table is located at elevations ranging from 22 to 40 m asl, while the ERI profiles conducted south of Menkaure, show almost high resistivity near the surface. The groundwater table is located at elevations ranging between 45 and 58 m asl. The aquifer layer shows electrical resistivities ranging between 10 and 50 Ohm.m. The considerable high change in the groundwater table is due to the rapid increases of topography from the Great Sphinx towards the Small Pyramids (Menkaure), where this part looks-like a scarp. The SSR Survey is transmitted to know the different velocities and types of the layers, which can help in knowing the saturated layers in the area. The GPR Survey is performed to delineate the water table, which gives good matching with the ERI results.

scholarly journals Shallow geophysical techniques to investigate the groundwater table at the Great Pyramids of Giza, Egypt

2019 ◽  
Vol 8 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Sharafeldin M. Sharafeldin ◽  
Khalid S. Essa ◽  
Mohamed A. S. Youssef ◽  
Hakan Karsli ◽  
Zein E. Diab ◽  
...  
Keyword(s):  
Water Table ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Groundwater Table ◽  
Near Surface ◽  
Groundwater Aquifer ◽  
Geophysical Surveys ◽  
Subsurface Layers ◽  
Average Water ◽  
Ground Penetrating

Abstract. The near-surface groundwater aquifer that threatened the Great Pyramids of Giza, Egypt, was investigated using integrated geophysical surveys. A total of 10 electrical resistivity imaging, 26 shallow seismic refraction, and 19 ground-penetrating radar surveys were conducted in the Giza Plateau. Collected data for each method were evaluated by state-of-the art processing and modeling techniques. A three-layer model depicts the subsurface layers and better delineates the groundwater aquifer and water table elevation. The resistivity of the aquifer layer and seismic velocity vary between 40 and 80 Ωm and between 1500 and 2500 m s−1, respectively. The average water table elevation is about +15 m, which is safe for the Great Sphinx, but it is still subjected to potential hazards from the Nazlet El-Samman suburb where the water table elevation reaches 17 m. A shallower water table at the Valley Temple and the tomb of Queen Khentkawes, with a low topographic relief, represents severe hazards. It can be concluded that a perched groundwater table is detected in the elevated topography to the west and southwest that might be due to runoff and capillary seepage.

Seismic reflection and ground‐penetrating radar imaging of a shallow aquifer

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1310-1317 ◽  
Author(s):  
Steven J. Cardimona ◽  
William P. Clement ◽  
Katharine Kadinsky‐Cade
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Low Frequency ◽  
Shallow Aquifer ◽  
Cone Penetrometer ◽  
Gradual Change ◽  
Cone Penetration ◽  
Geotechnical Data ◽  
Radar Images ◽  
Ground Penetrating

In 1995 and 1996, researchers associated with the US Air Force’s Phillips and Armstrong Laboratories took part in an extensive geophysical site characterization of the Groundwater Remediation Field Laboratory located at Dover Air Force Base, Dover, Delaware. This field experiment offered an opportunity to compare shallow‐reflection profiling using seismic compressional sources and low‐frequency ground‐penetrating radar to image a shallow, unconfined aquifer. The main target within the aquifer was the sand‐clay interface defining the top of the underlying aquitard at 10 to 14 m depth. Although the water table in a well near the site was 8 m deep, cone penetration geotechnical data taken across the field do not reveal a distinct water table. Instead, cone penetration tests show a gradual change in electrical properties that we interpret as a thick zone of partial saturation. Comparing the seismic and radar data and using the geotechnical data as ground truth, we have associated the deepest coherent event in both reflection data sets with the sand‐clay aquitard boundary. Cone penetrometer data show the presence of a thin lens of clays and silts at about 4 m depth in the north part of the field. This shallow clay is not imaged clearly in the low‐frequency radar profiles. However, the seismic data do image the clay lens. Cone penetrometer data detail a clear change in the soil classification related to the underlying clay aquitard at the same position where the nonintrusive geophysical measurements show a change in image character. Corresponding features in the seismic and radar images are similar along profiles from common survey lines, and results of joint interpretation are consistent with information from geotechnical data across the site.

Effectiveness of Geophysical Methods in Calcareous Harbor Fills

2013 ◽  
Author(s):  
Horst G. Brandes
Keyword(s):  
Ground Penetrating Radar ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Fill Material ◽  
Object Locations ◽  
Ground Penetrating

The effectiveness of electromagnetic (EM), ground penetrating radar (GPR) and seismic refraction (SR) were evaluated by surveying a shallow trench in which a number of objects of varying composition and size were buried. The trench was excavated in granular calcareous fill material. An experienced geophysical contractor was asked to provide blind predictions of object locations using each of the techniques in turn. GPR with a 400 MHz antenna was the most successful, followed by SR and EM surveying. GPR and SR were also carried out at the port of Hilo to investigate complex subsurface conditions.

Identification, investigation and classification of surface depressions and chalk dissolution features using integrated LiDAR and geophysical methods

2020 ◽  
Vol 53 (4) ◽  
pp. 620-644 ◽  
Author(s):  
Zoe Elizabeth Jeffery ◽  
Stephen Penn ◽  
David Peter Giles ◽  
Linley Hastewell
Keyword(s):  
Ground Penetrating Radar ◽  
Image Interpretation ◽  
Geophysical Methods ◽  
Integrated Approach ◽  
Study Data ◽  
Aerial Photographs ◽  
Geophysical Techniques ◽  
Karstic Features ◽  
Ground Penetrating

The chalk bedrock of the Hampshire Basin, southern England is an important aquifer and is highly susceptible to dissolution, making the development and presence of karstic features a widespread occurrence. These features are hazardous because they provide possible pathways to the underlying aquifer and therefore present potential site-specific contamination risks. There is also evidence of extensive extraction, through both mining and surface quarrying, of chalk, flint and clay over many centuries. Geophysical techniques consisting of electromagnetic (EM31) and ground-penetrating radar surveys were used to identify and characterize target features identified from desk study data. The ground-penetrating radar and EM31 interpretations allowed the classification of non-anthropogenic target features, such as diffuse buried sinkholes with disturbed and subsiding clay-rich infill and varying symmetrical and asymmetrical morphologies. We describe here the investigations of such features identified at Holme Farm, Stansted House, Hampshire. The combination of EM31 data and ground-penetrating radar profiles facilitated the identification of a palaeovalley, cavities and irregular rockhead. This investigation identified locations of aquifer contamination risk as some sinkholes have been sites for the illegal dumping of waste or the infiltration of fertilizers, leaking sewage pipes or animal waste. This potential source of contamination utilizes the sinkhole as a pathway into the highly transmissive White Chalk Subgroup of Hampshire and has caused contamination of the aquifer. We conclude that our integrated approach of geophysical techniques linked to aerial photographs and LiDAR image interpretation was highly effective in the location and characterization of dissolution structures, infilled former quarries and mining features at this site.

scholarly journals Formation of band ogives and associated structures at Bas Glacier d’Arolla, Valais, Switzerland

2002 ◽  
Vol 48 (161) ◽  
pp. 287-300 ◽  
Author(s):  
Becky Goodsell ◽  
Michael J. Hambrey ◽  
Neil F. Glasser
Keyword(s):  
Ground Penetrating Radar ◽  
Three Dimensional ◽  
Shear Zones ◽  
Glacier Surface ◽  
Glacier Tongue ◽  
Basal Ice ◽  
Planar Structures ◽  
Geophysical Techniques ◽  
Reverse Faulting ◽  
Ground Penetrating

AbstractStructural glaciological, sedimentological and geophysical techniques are used to provide new insight concerning the formation of band ogives and associated structures at Bas Glacier d’Arolla, Switzerland. Sedimentary stratification, crevasse traces and transverse foliation are identified as planar structures in the lower icefall and glacier tongue. Stratification and crevasse traces are progressively deformed into, and enhance, the transverse foliation found in the glacier tongue. Three-dimensional geometry has been defined using ground-penetrating radar, which portrays four main characteristics: (i) deep reflectors interpreted as the ice/bed interface, (ii) alternating reflection-rich and reflection-poor zones interpreted as ogives, (iii) up-glacier-dipping reflectors, interpreted as planar structures, and (iv) down-glacier-dipping reflectors of uncertain origin. At the glacier surface, each band ogive consists of a light and dark band. The dark bands contain more intense foliation which, on differential weathering, traps fine debris. Clasts and clear ice of basal character within dark ogive bands suggest that basal ice has been raised to the glacier surface. The most applicable model for the formation of band ogives at Bas Glacier d’Arolla is a refinement of Posamentier’s (1978) “reverse faulting” hypothesis. In this context, multiple shear zones are formed, through which basal ice is uplifted to the glacier surface to produce the dark, foliated ogive bands. This model fits observations reported from other glaciers with band ogives.

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